TABLE 1.

Stringent response components that contribute to virulence

PathogenStringent response machineryPathogenesis-related phenotype(s) associated with ppGppReference(s)
Gammaproteobacteria
    EHECRelA, SpoT,a DksAAdherence143
    UPECRelA, SpoT,a DksAAdherence1-3
    P. aeruginosaRelA, SpoT,a DksAQuorum sensing, biofilms, antibiotic tolerance18, 24, 27, 63, 202, 205
    Y. pestisRelA, SpoT,a DksAdBubonic infection, lung dissemination190
    V. choleraeRelA, SpoT,a RelV, DksAdMouse colonization56, 57, 74, 84, 179
    E. carotovora subsp. atrosepticabRelA, SpoT,a,d DksAdRot in potato tubers207
    S. flexneriRelA,d SpoT,d DksAIntercellular spread133, 175
    S. enterica serovar TyphimuriumRelA, SpoT,a DksAInvasion (SPI1 dependent), intracellular replication (SPI2 dependent)159, 182, 197, 200, 210, 223
    S. enterica serovar GallinarumRelA, SpoT,a DksAdInvasion (SPI1 independent), intracellular replication (SPI2 dependent)97
    L. pneumophilaRelA, SpoT,a DksAMacrophage transmission53, 81
    F. tularensisRelA, SpoT,a DksAdPhagosome escape in macrophages43
Actinobacteria
    M. tuberculosisRelMtb,a CarDPersistence in mice52, 185
Firmicutes
    L. monocytogenesRelA,a RelQ,d RelPdAdherence, intracellular survival19, 118, 149, 196
    S. aureusRelA,a RelQ,d RelPdEssential for viability in vitro44, 71, 114
    B. anthracisRelA,a RelQ,d RelPdSporulation114, 204
    C. difficileRelAaAntibiotic tolerance62
    E. faecalisRelA,a RelQAntibiotic tolerance, virulence in C. elegans4, 218
    S. pyogenesRelA,a RelQ,d RelPd186, 187
    S. pneumoniaeRelSpn,a RelQPulmonary infection of mice17
    S. mutansRelA,a RelQ, RelPBiofilms114-116, 145
Alphaproteobacteria
    Brucella sp.Rsh, DksAdMacrophage survival, persistence in mice59, 104
    R. etlicRelA,a DksAdNodule formation and nitrogen fixation25, 39, 137
    S. meliloticRelA,a DksAdNodule formation211, 213, 214
    A. tumefaciensbRelA,a DksAdTi plasmid transfer206, 221
Epsilonproteobacteria
    C. jejuniSpoT,a DksAAdherence, invasion, intracellular survival70, 188, 220
    H. pyloriSpoTaMacrophage survival138, 212, 224
Spirochetes
    B. burgdorferiSpoT or RelBbuaVirulence in mice34-36
  • a Bifunctional synthetase/hydrolase.

  • b Plant pathogen.

  • c Plant symbiont.

  • d Protein encoded by the species but yet to be studied.